At the present time, disposable drinking cups are in wide-spread use in fast food restaurants, soda fountains, delicatessen stores and similar establishments and are used to contain a beverage, either hot or cold, which is carried away by the customer. With rare exceptions, the hot beverage is usually coffee or tea and generates steam, and the cold beverage is usually carbonated and creates a gas.
A lid is ordinarily provided to close the open top of the drinking cup with a snap fit. It has been proposed to provide such a lid with a drinking opening adjacent to its periphery and which is opened by a person desirous of drinking from the cup. A valve ordinarily maintains this drinking opening closed. However, when a person opens the valve to drink the contents of the cup, steam or gas will escape through the opening and cause extreme discomfort to the user.
The present invention is founded on the belief that a relief valve in the top wall of the lid which is spaced from the drinking opening will greatly enhance the desirability of the lid in that as it is opened at the same time or slightly before the valve for the drinking opening is opened, it thus permits the escape of steam or gas therethrough.
The closest approach in the known art to a disposable drinking cup and lid of this type is disclosed in U.S. Pat. No. 3,905,512.
There are certain decanters which are not intended to be disposable; that is, discarded after one use, which provide a drinking opening and valve therefor in the top wall of the lid and a relief valve in a skirt depending from the top wall. However, these known devices include mechanism that is highly complicated in providing for opening of the relief valve before opening of the drinking opening. Drinking cups and lids of this decanter type are highly expensive as compared to the drinking cups and lids which are discarded after each use.
With the foregoing conditions in mind, the present invention has in view the following objectives:
1. To provide a drinking cup having an open top and a lid therefor including a top wall and a skirt depending therefrom, with the top wall having diametrically opposed drinking and relief valve openings.
2. To provide a drinking cup and valved lid of the type noted in which the drinking cup is of polystyrene beads which are expanded and molded by heat. This cup tapers downwardly from the edge defining the open top and thus is of a frusto-conical shape.
3. To provide, in a drinking cup and valved lid of the character aforesaid, a skirt having a downwardly opening peripheral groove which receives the upper edge portion of the cup with a snap fit.
4. To provide, in a drinking cup and valved lid of the kind noted, a lid which is made of a polystyrene sheet which is thin, flexible, and elastic to a high degree.
5. To provide, in a drinking cup and valved lid of the type described, a slit in the top wall of the lid which is arcuately shaped as a portion of a frusto-conical surface to provide a drinking opening and a valve member therefor which normally closes the opening, said slit being in close proximity to the periphery of the lid.
6. To provide, in a drinking cup and valved lid of the character aforesaid, a second arcuate slit which is spaced from the periphery of the lid a greater distance than is the arcuate slit for the drinking opening and is shaped as a portion of a cylinder; is in diametric alignment with said drinking opening slit; and is a straight cut. This slit provides a relief opening and a valve therefor.
7. To provide, in a drinking cup and valved lid of the kind described, a reinforcing rib projecting upwardly from the lid, of generally circular shape, and spaced from the periphery of the top wall.
8. To provide, in a drinking cup and valved lid of the type noted, a straight rib extending between said slits and arranged diametrically of the lid. This rib upstands from the material of the lid and accommodates deflection of the lid when force is applied to the top wall centrally thereof.
Various other more detailed objects and advantages of the invention such as arise in connection with carrying out the above-noted ideas in a practical embodiment will in part become apparent and in part be hereinafter stated as the description of the invention proceeds.